Forming patterned graphene layers

ABSTRACT

An apparatus and method for forming a patterned graphene layer on a substrate. One such method includes forming at least one patterned structure on a substrate; applying a layer of graphene on top of the at least one patterned structure on the substrate; heating the layer of graphene on top of the at least one patterned structure to remove one or more graphene regions proximate to the at least one patterned structure; and removing the at least one patterned structure to produce a patterned graphene layer on the substrate, wherein the patterned graphene layer on the substrate provides carrier mobility for electronic devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/310,885, filed Dec. 5, 2011, and incorporated by reference herein.

FIELD OF THE INVENTION

Embodiments of the invention generally relate to electronic devices and,more particularly, to nanoscale-patterned graphene.

BACKGROUND OF THE INVENTION

The exceptionally high intrinsic carrier mobility of graphene makes it apotentially promising material for high frequency electronic devicessuch as, for example, low-noise amplifiers for communicationapplications. However, there are many applications for nanoscale formsof carbon in which a graphene nanomesh (GNM) might be preferable to acontinuous layer of graphene.

GNM may be intrinsically semiconducting with a non-zero gap (unlikegraphene that has a zero gap with a vanishing density of states (DOS)),or quasi-metallic like graphene, with a vanishing DOS at the Fermienergy. Existing methods for nanomesh patterning of graphene, however,have drawbacks.

For example, existing approaches are not scalable to large areas.Additionally, in some existing approaches, graphene may be degraded bythe deposition and removal of the masking materials used. A drawback ofan existing approach in which graphene on a carbide-forming metal (M)layer is patterned by carbide-forming reactions with overlying metalnanodots is the narrow process window for graphene patterning versusgraphene re-growth, a consequence of the fact that graphene removal by acarbide formation reaction with the nanodot is reversible via amechanism in which the metal/metal carbide nanodot migrates into andmerges with the M support layer, leaving behind a “healed” graphenesurface reformed with carbon released from the nanodot.

Other existing approaches, such as those utilizing mobile metal nanodotsfor patterning, have disadvantages related to a lack of a means tocontrol the nanodot trajectories (and the patterns of removed grapheneleft in their wake).

Accordingly, given the disadvantages of the existing approaches, thereis a need for improved methods for nanoscale patterning of graphene.

SUMMARY OF THE INVENTION

In one aspect of the invention, a method for forming a patternedgraphene layer on a substrate is provided. The method includes the stepsof forming at least one patterned structure on a substrate; applying alayer of graphene on top of the at least one patterned structure on thesubstrate; heating the layer of graphene on top of the at least onepatterned structure to remove one or more graphene regions proximate tothe at least one patterned structure; and removing the at least onepatterned structure to produce a patterned graphene layer on thesubstrate, wherein the patterned graphene layer on the substrateprovides carrier mobility for electronic devices.

Another method for forming a patterned graphene layer on a substrateincludes applying graphene on top of a substrate to form a layer ofgraphene on the substrate; forming at least one patterned structure;heating the layer of graphene to remove one or more graphene regionsproximate to the at least one patterned structure; and removing the atleast one patterned structure to produce a patterned graphene layer onthe substrate, wherein the patterned graphene layer on the substrateprovides carrier mobility for electronic devices.

Yet another aspect of the invention includes a graphene nanomeshstructure on a substrate, wherein the graphene nanomesh structureprovides carrier mobility for electronic devices, and wherein thestructure includes a temporary patterned structure of a carbide-formingmetal or metal-containing alloy disposed on top of the substrate, andgraphene disposed on top of the substrate, wherein the graphene hasreacted with the at least one temporary patterned structure of acarbide-forming metal or metal-containing alloy to remove grapheneregions proximate to the at least one patterned structure of acarbide-forming metal or metal-containing alloy to produce a graphenenanomesh structure on the substrate.

Also, another aspect of the invention includes a patterned graphenestructure on a substrate, wherein the patterned graphene structureprovides carrier mobility for electronic devices, and wherein thestructure includes a temporary patterned structure of a carbide-formingmetal or metal-containing alloy disposed on top of the substrate, andgraphene disposed on top of the substrate, wherein the graphene hasreacted with the at least one temporary patterned structure of acarbide-forming metal or metal-containing alloy to remove grapheneregions proximate to the at least one patterned structure of acarbide-forming metal or metal-containing alloy to produce a patternedgraphene layer on the substrate.

These and other objects, features and advantages of the presentinvention will become apparent from the following detailed descriptionof illustrative embodiments thereof, which is to be read in connectionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example graphene nanomesh (GNM),according to an embodiment of the present invention;

FIG. 2 is a diagram illustrating a passivated and doped graphenenanomesh, according to an embodiment of the present invention;

FIG. 3 is a diagram illustrating a functionalized graphene nanomesh,according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating the “under” technique for forming apatterned graphene layer, according to an embodiment of the presentinvention;

FIG. 5 is a diagram illustrating the “over” technique for forming apatterned graphene layer, according to an embodiment of the presentinvention;

FIG. 6 is a diagram illustrating two examples of patterned metaltemplates that may be used and reused to form patterned graphene layers,according to an embodiment of the present invention;

FIG. 7 is a diagram illustrating a first use of a patterned metaltemplate for forming a patterned graphene layer, according to anembodiment of the present invention;

FIG. 8 is a diagram illustrating a second use of a patterned metaltemplate for forming a patterned graphene layer, according to anembodiment of the present invention;

FIG. 9 is a flow diagram illustrating techniques for forming a patternedgraphene layer on a substrate, according to an embodiment of the presentinvention; and

FIG. 10 is a flow diagram illustrating techniques for forming apatterned graphene layer on a substrate, according to an embodiment ofthe present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

An aspect of the invention includes using metal-induced reactions fornanomesh patterning of graphene. Graphene nanomeshes (GNMs) are carbonbased structures that are made by creating holes in a graphene sheet ina periodic way (as illustrated, for example, in FIG. 1). Fourgeometrical parameters characterize a GNM: the hole lattice, size,shape, and lattice constant.

As described herein, aspects of the invention include multiple relatedmethods for forming a patterned graphene layer on an insulating orcopper- (Cu-)based substrate. In addition to copper, embodiments of theinvention can include the use of non-carbide forming metals or metalalloys. Each method relies on the fact that regions of graphene incontact with nickel- (Ni-)like materials are unstable at elevatedtemperatures and easily removed by mechanisms such as metal-catalyzeddecomposition into carbon-containing volatiles (typically in ahydrogen-containing environment at elevated temperature) and/or reactionand/or complexation with Ni-like materials to form solublized carbonand/or carbides.

As used herein, Ni-like refers to carbide forming metals or metalalloys. Additionally, as used herein, a mixed material layer refers to agraphene layer plus a patterned layer of a carbide forming metal ormetal alloy material.

As detailed herein, embodiments of the present invention includetechniques for forming a patterned graphene layer on an insulatingsubstrate wherein patterned structures of Ni-like materials can beformed and/or applied either under or on top of a layer of graphene.

Methods with Ni-like structures under the graphene have the advantagesthat the positions of the Ni-like structures are fixed (versus mobile)and that there is no chance of Ni-like structure interaction withgraphene during the Ni-like structure fabrication because the metalpatterning or self-assembly is done before the graphene is on thesubstrate.

Methods with Ni-like structures over the graphene have the advantagesthat the patterning can be done on generic graphene wafers (for example,graphene bonded to a carrier substrate), but such Ni-like structures maybe mobile and there may be less flexibility in the Ni-like structurefabrication methods when the Ni-like structures are formed on top of agraphene layer. For example, for self-assembled Ni-like structures, ablanket layer of thin Ni on the graphene might react with the graphenebefore it self-assembled into Ni nanodots.

GNM materials are typically most useful when situated on insulatingsubstrates. When the substrate for the two methods just described isinsulating, the patterned graphene can stay in place on the substrate onwhich it was patterned; GNM on an insulating substrate can thus beformed directly with no need for subsequent transfer to an insulatingsubstrate and/or special handling to remove conductive upper layers ofthe substrate underlying the GNM.

Patterning of copper- (Cu-)supported graphene (by way of example,graphene on a Cu foil substrate) by Ni-like structures is alsocontemplated. In this instance, the GNM would typically be transferredto an insulating substrate in a process sequence that might include thesteps of bonding the GNM to a temporary support layer, removing the Cusupport by a process such as Cu etching to leave a GNM/support layerstructure, bonding the GNM to a permanent handle substrate, and removingthe temporary support layer. An advantage of this embodiment is that itis compatible with roll-to-roll fabrication methods.

FIGS. 1-3 depict graphene nanomesh (GNM) materials that may befunctionalized (FIGS. 2-3) or not (FIG. 1). Accordingly, FIG. 1 is adiagram illustrating an example of a non-functionalized graphenenanomesh (GNM) 102, according to an embodiment of the present invention.FIG. 2 is a diagram illustrating a passivated and doped graphenenanomesh 202, with dopant moiety 205 and passivating moieties 210 thatmay be formed from GNM similar to GNM 102. FIG. 3 is a diagramillustrating a functionalized graphene nanomesh 302, withfunctionalizing moieties 305 (shown both end-on and in plan view) thatmay be formed from GNM similar to GNM 102.

FIG. 4 is a diagram illustrating the “under” technique for forming apatterned graphene layer, according to an embodiment of the presentinvention. By way of illustration, in the “under” technique,self-assembled Ni-like structures are formed from a blanket layer ofNi-like material, and the patterned graphene can stay on the substrate.Specifically, the example in FIG. 4 depicts Ni 402, SiO₂ 404, Si 406 andgraphene (G) 408. Illustrated step 410 includes depositing a thin layerof Ni onto SiO₂ (on top of the Si substrate).

Illustrated step 412 includes agglomerating the Ni into self-assemblednanodots to produce patterned Ni structures 403. Illustrated step 414includes transferring and/or bonding a graphene layer to the Ninanodot/substrate layer. Illustrated step 416 includes patterning thegraphene via a localized reaction with the Ni. Illustrated step 418includes etching away the Ni, leaving the patterned graphene layer.While steps 410 and 412 of FIG. 4 show patterned Ni structures 403formed by self-assembly from a blanket thin film (via known processes),this is only one of several methods that may be used to form thepatterned Ni structures.

FIG. 5 is a diagram illustrating the “over” technique for forming apatterned graphene layer, according to an embodiment of the presentinvention. By way of illustration, in the “over” technique, the Ni-likestructures are deposited from a solution, and the patterned graphene canstay on the substrate. Specifically, the example in FIG. 5 depicts Ni502, SiO₂ 504, Si 506 and graphene (G) 508.

Illustrated step 512 includes depositing a layer of graphene onto SiO₂(on top of the Si substrate). Illustrated step 514 includes formingpatterned Ni structures 503 by, for example, depositing self-assemblingNi nanodots from solution. Illustrated step 516 includes patterning thegraphene via a localized reaction with the Ni. Illustrated step 518includes etching away the Ni, leaving the patterned graphene layer.While step 512 of FIG. 5 shows patterned Ni structures 503 formed byself-assembling Ni nanodots from solution (via known processes), this isonly one of several methods that may be used to form the patterned Nistructures.

FIG. 6 is a diagram illustrating two examples of patterned metaltemplates that may be used and reused to form patterned graphene layers,according to an embodiment of the present invention. Such templates maybe useful in cases where the desired metal patterns cannot easily beformed by self-assembly techniques, making it costly to fabricate a newpatterned metal layer each time an individual graphene layer is to bepatterned. By way of illustration, 610 in FIG. 6 depicts a planartemplate that includes an array of Ni patterns embedded in a dielectricon a base substrate, and 612 in FIG. 6 depicts a non-planar stamp-liketemplate that includes an array of Ni patterns extending above a basesubstrate. As shown, FIG. 6, FIG. 7 and FIG. 8 depict Ni 602, SiO₂ 604,Si 606 and graphene 608.

FIG. 7 is a diagram illustrating how patterned metal template 610 ofFIG. 6 may be used in a first method to form a patterned graphene layer,according to an embodiment of the present invention. By way ofillustration, FIG. 7 depicts a graphene layer being applied to thetemplate of Ni-like structures and removed after patterning.Specifically, in the FIG. 7 example, illustrated step 712 includesapplying graphene to the template. Illustrated step 714 includespatterning the graphene via a localized reaction with the Ni. Further,illustrated step 716 includes removing (for example, peeling off) thegraphene nanomesh.

FIG. 8 is a diagram illustrating how patterned metal template 610 ofFIG. 6 may be used in a second method to form a patterned graphenelayer, according to an embodiment of the present invention. By way ofillustration, FIG. 8 depicts the template being applied to a supportedgraphene layer and removed after patterning. Specifically, in the FIG. 8example, illustrated step 812 includes applying patterned metal template610 to the graphene layer. Illustrated step 814 includes patterning thegraphene via a localized reaction with the Ni. Further, illustrated step816 includes removing the template.

In both the example of FIG. 7 and the example of FIG. 8, the templatemay be refurbished after use by annealing, for example, in Ar/H₂ atapproximately 800 degrees Celsius, to remove any dissolved carbon.

The process used to remove the patterned structure of a carbide-formingmetal or metal-containing alloy after the graphene patterning reactionwill depend on the form and composition of the patterned metalstructure. Template structures such as those shown in FIGS. 6-8 may beremoved by mechanical separation. More commonly, the patterned structureof a carbide-forming metal or metal-containing alloy such as those shownin 416 of FIG. 4 and 516 of FIG. 5 is removed after graphene patterningby performing a wet etch process that etches the patterned structure ofa carbide-forming metal or metal-containing alloy selectively tographene and to the substrate on which the graphene is disposed. Forpatterned structures of Ni (such as shown in 416 of FIG. 4 and 516 ofFIG. 5), etchants can include aqueous solutions of HCl, FeCl₃, aquaregia, or commercial etchants such as Transene Thin Film Nickel EtchantTFB, Transene Thin Film Nickel Etchant TFG, or Transene Nickel EtchantType I.

As detailed herein, Ni-like structures may be patternedlithographically, by deposition or etching through a mask. However, in apreferred embodiment of the present invention, lithography is avoidedand the Ni-like structures are self-assembled. Self-assembly of Ni-likestructures can be accomplished, for example, by deposition of preformedNi-like nanoparticles from solution (by spraying, spinning, dip coat,etc.), where preformed nanoparticles may further include surface layersof additional materials that are not Ni-like (for example,functionalizing molecules to facilitate suspension in solution).

For self-assembly of nickel nanoparticles on graphene or oxide surfaces,the nanoparticles can be coated with a bifunctional group which at oneend forms a covalent bond with the nanoparticle and at the other end hasa functionality which can form an electrostatic or covalent bond with agraphene or oxide surface. For example, for self-assembly of nickelnanoparticles on graphene surface, nanoparticles may be reacted withbifunctional compounds having a thiol (—SH) group on one end (to form abond with the nanoparticle) and a functionality such as a diazonium salt(—N₂ ⁺X⁻, where X⁻ is an inorganic or organic anion such as a halogen)on the other end (to allow charge transfer bonding to graphene).

For self-assembly on oxide surfaces, especially on metal oxide surfaces,the nanoparticles can be again coated with bifunctional molecules havinga thiol group at one end. However, the other end of the bifunctionalmolecule can include a phosphonic acid (—PO(OH)₂) group to help thenanoparticle form a covalent bond to the metal oxide (hafnium oxide,aluminum oxide, etc.), resulting in self-assembly of nanoparticles onthe oxide surface.

Alternatively, self-assembly of Ni-like structures can be accomplishedby the blanket deposition of a thin (1-30 nanometers (nm) layer) filmNi-like layer followed by annealing at an elevated temperature in anenvironment to agglomerate the thin film into nanodots. Nanodot size andspacing may be controlled by Ni film thickness (typically smaller andmore closely spaced dots for thinner Ni films), annealing conditions(temperature and gas environment), and the wetting properties of thesurface on which the Ni film is deposited. For example, Ni nanodotformation on Si substrates can include coating with 10-20 nm of SiO₂ bydepositing 3-20 nm Ni and annealing at 850 degrees Celsius in N₂ fortimes of 20-30 seconds. Other methods of metal nanodot formationinclude, for example, a plasma-assisted Ni nanoparticle formationprocess developed by, in which Ni is slowly sputtered onto substratesexposed to a plasma.

As detailed herein, graphene patterning via a localized reaction withNi-like materials occurs at elevated temperatures in an environment bysuch mechanisms as metal-catalyzed decomposition into carbon-containingvolatiles (typically in a hydrogen-containing environment) and/orreaction and/or complexation with Ni-like materials to form solublizedcarbon and/or carbides. Environments may include, for example, a vacuum,gases such as Ar, N₂, He, H₂, and mixtures of these gases. Temperaturesin the range 500-1000 degrees Celsius, and preferably in the range600-800 degrees Celsius may be employed for times ranging from a fewhours for temperatures at the low end of the range to a few seconds fortemperatures at the high end of the range. Hydrogen containingenvironments may be preferable because they facilitate the production ofcarbon-containing volatiles that are more completely removed from thereaction area than carbon remaining in the metal nanodot.

FIG. 9 is a flow diagram illustrating techniques for forming a patternedgraphene layer on a substrate (for example, an insulating substrate),according to an embodiment of the present invention. Step 902 includesforming at least one patterned structure of a carbide-forming metal ormetal-containing alloy on a substrate. An array of Ni nanodots would bean example of a patterned carbide-forming metal or metal-containingalloy structure. Arrays of metal nanodots may be formed by applying aliquid suspension of nanodots and drying, or by forming a thin (forexample, 1-10 nm) film of a metal and gently heating it up so that itbreaks up into metal dots.

The patterned structure of a carbide-forming metal or metal-containingalloy can be patterned lithographically by deposition or etching througha mask. Further, the patterned structure of a carbide-forming metal ormetal-containing alloy can include material selected from a groupcontaining Ni, Fe, Co, Pt, and an alloy of a combination thereof.

Also, the patterned structure of a carbide-forming metal ormetal-containing alloy can be self-assembled. Self-assembly of thepatterned structure of a carbide-forming metal or metal-containing alloycan include deposition of multiple preformed carbide-forming metal ormetal-containing alloy nanoparticles from solution, for example, byspraying, spinning, dip coat, etc.

Preformed carbide-forming metal or metal-containing alloy nanoparticlescan include at least one surface layer of additional material that isnot carbide-forming metal or metal-containing alloy. By way of example,this can include functionalizing molecules to facilitate suspension insolution. Additionally, self-assembly of the at least one patternedstructure of a carbide-forming metal or metal-containing alloy caninclude blanket deposition of a film of a carbide-forming metal ormetal-containing alloy layer, and annealing the film at an elevatedtemperature in an environment to agglomerate the film into multiplenanodots. In such an embodiment, the film of a carbide-forming metal ormetal-containing alloy layer can include a film in a range ofapproximately one nanometer to approximately 30 nanometers.

Step 904 includes applying a layer of graphene on top of the at leastone patterned structure of a carbide-forming metal or metal-containingalloy on the substrate. Step 906 includes heating the layer of grapheneon top of the at least one patterned structure of a carbide-formingmetal or metal-containing alloy in an environment to remove grapheneregions proximate to the at least one patterned structure of acarbide-forming metal or metal-containing alloy.

Step 908 includes removing the at least one patterned structure of acarbide-forming metal or metal-containing alloy (and/or their residues)to produce a patterned graphene layer on the substrate, wherein thepatterned graphene layer on the substrate provides carrier mobility forelectronic devices. Removing the patterned structure of acarbide-forming metal or metal-containing alloy to produce a patternedgraphene layer on the insulating substrate can include performing a wetetch process that etches the patterned structure of a carbide-formingmetal or metal-containing alloy selectively to graphene and to thesubstrate on which the graphene is disposed.

The techniques depicted in FIG. 9 can also include selecting asubstrate.

FIG. 10 is a flow diagram illustrating techniques for forming apatterned graphene layer on a substrate (for example, an insulatingsubstrate), according to an embodiment of the present invention. Step1002 includes applying graphene on top of a substrate to form a layer ofgraphene on the substrate. In an example embodiment, the substrateincludes a Cu-containing layer positioned under the layer of graphene.

Step 1004 includes forming at least one patterned structure of acarbide-forming metal or metal-containing alloy. In an exampleembodiment, a mixed material layer including at least one patternedstructure of a carbide-forming metal or metal-containing alloy canfurther include a graphene layer on the insulating substrate in contactwith at least one patterned structure of a carbide-forming metal ormetal-containing alloy disposed on a second substrate. Such an aspectcan be carried out via use of a patterned Ni (or carbide-forming metalor metal-containing alloy) stamp.

The techniques depicted in FIG. 10 include a substrate that can bedielectric or a non-carbide forming metal.

As also detailed above in connection with the techniques of FIG. 9, thepatterned Ni-like structure can be patterned lithographically bydeposition or etching through a mask. Further, the patterned structureof a carbide-forming metal or metal-containing alloy can includematerial selected from a group containing Ni, Fe, Co, Pt, and an alloyof a combination thereof.

Also, the patterned structure of a carbide-forming metal ormetal-containing alloy can be self-assembled. Self-assembly of thepatterned structure of a carbide-forming metal or metal-containing alloycan include deposition of multiple preformed carbide-forming metal ormetal-containing alloy nanoparticles from solution, for example, byspraying, spinning, dip coat, etc. Preformed carbide-forming metal ormetal-containing alloy nanoparticles can include at least one surfacelayer of additional material that is not carbide-forming metal ormetal-containing alloy. By way of example, this can includefunctionalizing molecules to facilitate suspension in solution.

Additionally, self-assembly of the at least one patterned structure of acarbide-forming metal or metal-containing alloy can include blanketdeposition of a film of an carbide-forming metal or metal-containingalloy layer, and annealing the film at an elevated temperature in anenvironment to agglomerate the film into multiple nanodots. In such anembodiment, the film of a carbide-forming metal or metal-containingalloy layer can include a film in a range of approximately one nanometerto approximately 30 nanometers.

Step 1006 includes heating the layer of graphene in an environment toremove graphene regions proximate to the at least one patternedstructure of a carbide-forming metal or metal-containing alloy.

Step 1008 includes removing the at least one patterned structure of acarbide-forming metal or metal-containing alloy to produce a patternedgraphene layer on the substrate, wherein the patterned graphene layer onthe substrate provides carrier mobility for electronic devices. Removingthe patterned structure of a carbide-forming metal or metal-containingalloy to produce a patterned graphene layer on the insulating substratecan include performing a wet etch process that etches the patternedstructure of a carbide-forming metal or metal-containing alloyselectively to graphene and to the substrate on which the graphene isdisposed.

The techniques depicted in FIG. 10 can additionally include thesubstrate containing an insulating overlayer. By way of example, asubstrate with insulating overlayer includes Si/SiO₂.

Additionally, as detailed herein, embodiments of the invention include agraphene nanomesh structure formed with patterned structures ofcarbide-forming metal or metal-containing alloy materials either underor on top of a layer of graphene.

By way of example, in an embodiment of the invention, a graphenenanomesh structure on a substrate, wherein the graphene nanomeshstructure provides carrier mobility for electronic devices, includes atemporary patterned structure of a carbide-forming metal ormetal-containing alloy disposed on top of the substrate, and graphenedisposed on top of the substrate, wherein the graphene has reacted withthe at least one temporary patterned structure of a carbide-formingmetal or metal-containing alloy to remove graphene regions proximate tothe at least one patterned structure of a carbide-forming metal ormetal-containing alloy to produce a graphene nanomesh structure on thesubstrate.

Additionally, in another embodiment of the invention, a patternedgraphene structure on a substrate, wherein the patterned graphenestructure provides carrier mobility for electronic devices, includes atemporary patterned structure of a carbide-forming metal ormetal-containing alloy disposed on top of the substrate, and graphenedisposed on top of the substrate, wherein the graphene has reacted withthe at least one temporary patterned structure of a carbide-formingmetal or metal-containing alloy to remove graphene regions proximate tothe at least one patterned structure of a carbide-forming metal ormetal-containing alloy to produce a patterned graphene layer on thesubstrate.

Although illustrative embodiments of the present invention have beendescribed herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those preciseembodiments, and that various other changes and modifications may bemade by one skilled in the art without departing from the scope orspirit of the invention.

What is claimed is:
 1. A method, comprising: forming at least onepatterned structure on a substrate; applying a layer of graphene on topof the at least one patterned structure on the substrate; heating thelayer of graphene on top of the at least one patterned structure toremove one or more graphene regions proximate to the at least onepatterned structure; and removing the at least one patterned structureto produce a patterned graphene layer on the substrate, wherein thepatterned graphene layer on the substrate provides carrier mobility forelectronic devices.
 2. The method of claim 1, wherein the substratecomprises an insulating substrate.
 3. The method of claim 1, wherein thesubstrate includes an insulating overlayer.
 4. The method of claim 1,wherein the at least one patterned structure comprises at least onepatterned structure of a carbide-forming metal or metal-containingalloy.
 5. The method of claim 4, wherein the at least one patternedstructure of a carbide-forming metal or metal-containing alloy isself-assembled.
 6. The method of claim 5, wherein self-assembly of theat least one patterned structure of a carbide-forming metal ormetal-containing alloy comprises deposition of multiple preformedcarbide-forming metal or metal-containing alloy nanoparticles fromsolution.
 7. The method of claim 6, wherein preformed carbide-formingmetal or metal-containing alloy nanoparticles include at least onesurface layer of additional material that is not carbide-forming metalor metal-containing alloy.
 8. The method of claim 5, whereinself-assembly of the at least one patterned structure of acarbide-forming metal or metal-containing alloy comprises: blanketdeposition of a film of a carbide-forming metal or metal-containingalloy layer; and annealing the film at an elevated temperature in anenvironment to agglomerate the film into multiple nanodots.
 9. Themethod of claim 4, wherein the at least one patterned structure of acarbide-forming metal or metal-containing alloy comprises materialselected from a group containing Ni, Fe, Co, Pt, and an alloy of acombination thereof.
 10. The method of claim 1, wherein removing the atleast one patterned structure to produce a patterned graphene layer onthe substrate comprises performing a wet etch process that etches the atleast one patterned structure selectively to graphene and to thesubstrate on which the graphene is disposed.
 11. A method, comprising:applying graphene on top of a substrate to form a layer of graphene onthe substrate; forming at least one patterned structure; heating thelayer of graphene to remove one or more graphene regions proximate tothe at least one patterned structure; and removing the at least onepatterned structure to produce a patterned graphene layer on thesubstrate, wherein the patterned graphene layer on the substrateprovides carrier mobility for electronic devices.
 12. The method ofclaim 11, wherein the substrate comprises a Cu-containing layerpositioned under the layer of graphene.
 13. The method of claim 11,wherein the substrate comprises at least one of an insulating substrateand an insulating overlayer.
 14. The method of claim 11, wherein the atleast one patterned structure comprises at least one patterned structureof a carbide-forming metal or metal-containing alloy.
 15. The method ofclaim 14, wherein the at least one patterned structure of acarbide-forming metal or metal-containing alloy is self-assembled. 16.The method of claim 15, wherein self-assembly of the at least onepatterned structure of a carbide-forming metal or metal-containing alloycomprises deposition of multiple preformed carbide-forming ormetal-containing alloy nanoparticles from solution.
 17. The method ofclaim 16, wherein preformed carbide-forming or metal-containing alloynanoparticles include at least one surface layer of additional materialthat is not carbide-forming or metal-containing alloy.
 18. The method ofclaim 15, wherein self-assembly of the at least one patterned structureof a carbide-forming metal or metal-containing alloy comprises: blanketdeposition of a film of a carbide-forming or metal-containing alloylayer; and annealing the film at an elevated temperature in anenvironment to agglomerate the film into multiple nanodots.
 19. Themethod of claim 14, wherein the at least one patterned structure of acarbide-forming metal or metal-containing alloy comprises materialselected from a group containing Ni, Fe, Co, Pt, and an alloy of acombination thereof.
 20. The method of claim 11, wherein removing the atleast one patterned structure to produce a patterned graphene layer onthe substrate comprises performing a wet etch process that etches the atleast one patterned structure selectively to graphene and to thesubstrate on which the graphene is disposed.